Combine the coconut milk and non-dairy milk of choice in a medium saucepan over medium heat until warmed through.
In a medium bowl, whisk together the eggs and granulated sugar until well combined. Then whisk in the cornstarch until smooth.
Slowly pour about half of the hot milk mixture into the eggs while continuously whisking (this will prevent the eggs from scrambling). Return the custard mixture back to the saucepan with the rest of the warmed milk and place it over medium-low heat.
Whisk constantly for about 8-10 minutes or until the pudding has thickened. You’ll know it’s done when it coats the back of a spoon.
Remove the pudding from the heat and whisk in the dairy-free butter, vanilla extract, and salt. Then pour the pudding through a fine-mesh sieve to remove any lumps for a silky smooth texture.
Transfer it to a large bowl and cover it with a piece of plastic wrap that touches the surface of the pudding. This helps to prevent a layer of film from forming on the top.
Let the pudding come to room temperature before transferring it to the fridge to allow it to cool completely. This will take about 2-3 hours. It will thicken up more as it cools.
It's time to assemble. Add a layer of banana pudding to the bottom of your glasses followed by a layer of crumbled vanilla wafers, a dollop of Coco Whip, and then a layer of thin banana slices. Repeat this process until you have the number of layers you'd like.